U.S. patent number 9,755,114 [Application Number 14/763,157] was granted by the patent office on 2017-09-05 for method for producing a plurality of optoelectronic components and optoelectronic component.
This patent grant is currently assigned to OSRAM OPTO SEMICONDUCTORS GMBH. The grantee listed for this patent is OSRAM Opto Semiconductors GmbH. Invention is credited to Tony Albrecht, Thomas Schlereth, Albert Schneider.
United States Patent |
9,755,114 |
Albrecht , et al. |
September 5, 2017 |
Method for producing a plurality of optoelectronic components and
optoelectronic component
Abstract
The invention relates to a method for producing a plurality of
optoelectronic components, comprising the following steps:
--providing an auxiliary support wafer (1) having contact
structures (4), wherein the auxiliary support wafer comprises
glass, sapphire, or a semiconductor material, --applying a
plurality of radiation-emitting semiconductor bodies (5) to the
contact structures (4), --encapsulating an least the contact
structures (4) with a potting mass (10), and --removing the
auxiliary support wafer (1). The invention further relates to an
optoelectronic component.
Inventors: |
Albrecht; Tony (Bad Abbach,
DE), Schlereth; Thomas (Regensburg, DE),
Schneider; Albert (Thalmassing, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
OSRAM Opto Semiconductors GmbH |
Regensburg |
N/A |
DE |
|
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Assignee: |
OSRAM OPTO SEMICONDUCTORS GMBH
(Regensburg, DE)
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Family
ID: |
49876569 |
Appl.
No.: |
14/763,157 |
Filed: |
December 12, 2013 |
PCT
Filed: |
December 12, 2013 |
PCT No.: |
PCT/EP2013/076431 |
371(c)(1),(2),(4) Date: |
July 23, 2015 |
PCT
Pub. No.: |
WO2014/114407 |
PCT
Pub. Date: |
July 31, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150357530 A1 |
Dec 10, 2015 |
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Foreign Application Priority Data
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Jan 24, 2013 [DE] |
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10 2013 100 711 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
33/56 (20130101); H01L 33/62 (20130101); H01L
33/0095 (20130101); H01L 33/502 (20130101); H01L
33/486 (20130101); H01L 24/97 (20130101); H01L
33/54 (20130101); H01L 2933/005 (20130101); H01L
25/0753 (20130101); H01L 2924/12041 (20130101); H01L
2224/48247 (20130101); H01L 2224/16245 (20130101); H01L
2224/49113 (20130101); H01L 2224/48137 (20130101); H01L
33/50 (20130101); H01L 2224/48091 (20130101); H01L
2924/18301 (20130101); H01L 2924/181 (20130101); H01L
2224/48091 (20130101); H01L 2924/00014 (20130101); H01L
2924/12041 (20130101); H01L 2924/00 (20130101); H01L
2924/181 (20130101); H01L 2924/00012 (20130101) |
Current International
Class: |
H01L
33/56 (20100101); H01L 33/48 (20100101); H01L
33/54 (20100101); H01L 23/00 (20060101); H01L
33/00 (20100101); H01L 33/50 (20100101); H01L
33/62 (20100101); H01L 25/075 (20060101) |
Field of
Search: |
;257/88,99 ;438/35 |
References Cited
[Referenced By]
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WO |
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Other References
Schnitzer et al: "30% external quantum efficiency from surface
textured, thin-film light-emitting diodes"; Appl. Phys. Lett., 63
(15), 18; Oct. 18, 1993, pp. 2174-2176. cited by applicant.
|
Primary Examiner: Parker; Kenneth
Assistant Examiner: Kim; Young W
Attorney, Agent or Firm: McDermott Will & Emery LLP
Claims
The invention claimed is:
1. A method for producing a plurality of optoelectronic components
having the following steps: providing an auxiliary carrier wafer
having contact structures; applying a plurality of
radiation-emitting semiconductor bodies to the contact structures;
encapsulating the contact structures with a mechanically
stabilizing material which terminates flush with a surface of the
contact structures, the mechanically stabilizing material being a
housing material; applying a potting mass to the surface, which is
formed by the contact structures and the mechanically stabilizing
material, such that the potting mass terminates flush with a front
side of the semiconductor bodies; and removing the auxiliary
carrier wafer.
2. The method according to claim 1, wherein the contact structures
have a first metallic layer and a second metallic layer, wherein
the second metallic layer is galvanically deposited on the first
metallic layer.
3. The method according to claim 2, wherein the second metallic
layer has lateral flanks having an undercut.
4. The method according to claim 1, wherein the potting mass is
reflective and/or wavelength-converting.
5. The method according to claim 1, wherein the potting mass is
applied using one of the following methods: casting, dispensing,
jetting, molding.
6. The method according to claim 1, wherein the auxiliary carrier
wafer is removed by one of the following methods: laser liftoff,
etching, grinding.
7. The method according to claim 1, wherein a wavelength-converting
layer is arranged in a light path of the semiconductor bodies.
8. The method according to claim 1, wherein an optical element is
arranged in the light path of each semiconductor body.
9. The method according to claim 8, wherein the optical elements
are molded above the semiconductor bodies.
10. The method according to claim 1, wherein the semiconductor
bodies are implemented as flip-chips.
11. The method according to claim 1, wherein the semiconductor
bodies have an electrical contact or at least two electrical
contacts on their front side.
12. The method according to claim 1, wherein an upper edge of the
potting mass extends up to an upper edge of the semiconductor
bodies.
13. The method according to claim 1, wherein each later component
has a plurality of semiconductor bodies.
14. An optoelectronic component, which is produced using a method
according to claim 1.
15. A method for producing a plurality of optoelectronic components
having the following steps: providing an auxiliary carrier wafer
having contact structures; applying a plurality of
radiation-emitting semiconductor bodies to the contact structures;
encapsulating the contact structures with a mechanically
stabilizing material which terminates flush with a surface of the
contact structures, the mechanically stabilizing material being a
housing material; applying a reflective potting mass to the
surface, which is formed by the contact structures and the
mechanically stabilizing material, such that the potting mass
terminates flush with a front side of the semiconductor bodies; and
removing the auxiliary carrier wafer.
Description
A method for producing a plurality of optoelectronic components and
an optoelectronic component are specified.
A method for producing a plurality of optoelectronic components and
an optoelectronic component are described, for example, in the
following documents: WO 2007/025515, WO 2012/000943.
A cost-effective method is to be specified for producing an
optoelectronic component. Furthermore, an optoelectronic component
having a compact construction is to be specified.
These objects are achieved by a method having the steps of patent
claim 1 and by an optoelectronic component having the features of
patent claim 18.
Advantageous refinements and embodiments of the method and of the
optoelectronic component are specified in the dependent claims.
In the method for producing a plurality of optoelectronic
components, an auxiliary carrier wafer having contact structures is
provided. The auxiliary carrier wafer preferably has glass,
sapphire, or a semiconductor material, for example, silicon. The
auxiliary carrier wafer can also consist of glass, sapphire, or a
semiconductor material, for example, silicon. A plurality of
radiation-emitting semiconductor bodies is applied to the contact
structures. The radiation-emitting semiconductor bodies are capable
of emitting electromagnetic radiation of a first wavelength range
from a radiation exit surface. At least the contact structures are
encapsulated using a potting mass. The auxiliary carrier wafer is
preferably removed from the resulting composite. The auxiliary
carrier wafer is particularly preferably completely removed from
the composite of the later components.
The method makes use of the concept that an auxiliary carrier wafer
is used to produce the plurality of optoelectronic components
instead of a prefinished housing. The auxiliary carrier wafer is
generally no longer contained later in the finished component in
this case. The auxiliary carrier wafer is used for the mechanical
stabilization of the semiconductor body during the production of
the optoelectronic components. Furthermore, the individual method
steps for producing the optoelectronic components can take place
easily on the wafer level because of the auxiliary carrier wafer.
Material and processing costs are thus advantageously saved and
overall optimization of the individual process steps of the
production method is possible. In addition, the individual
manufacturing units, for example, the auxiliary carrier wafer, can
be easily scaled.
Furthermore, a particularly compact and/or flat construction of the
finished components is achieved using the proposed method. A
compact construction advantageously results in very good heat
dissipation from the semiconductor body in operation of the
finished component.
Furthermore, using the proposed method, the use of prefinished
conductor frames or ceramic panels for mechanical stabilization of
the semiconductor bodies can advantageously be omitted. The use of
through-contacted silicon panels is advantageously also not
necessary in the proposed method. The finished component is
particularly preferably free of a conventional housing.
The contact structures are particularly preferably used for the
later electrical contacting of the semiconductor bodies. The
contact structures are constructed, for example, from individual
contact structure elements, which are electrically insulated from
one another. Particularly preferably, two contact structure
elements are associated with each semiconductor body. In particular
if each later component has a single semiconductor body, precisely
two contact structure elements are preferably associated with each
individual semiconductor body.
Each semiconductor body is particularly preferably attached using a
mounting surface, which is opposite to its radiation exit surface,
in an electrically conductive manner to a contact structure
element. The radiation exit surface of the semiconductor body is
generally part of a front side of the semiconductor body in this
case, which can have partial regions, however, for example, a bond
pad, from which radiation cannot exit. The front side is opposite
to the mounting surface.
For example, the contact structures have a first metallic layer and
a second metallic layer, wherein the second metallic layer is
galvanically deposited on the first metallic layer. The first
metallic layer particularly preferably has a thickness between 50
nm inclusive and 500 nm inclusive. The first metallic layer can
have one of the following materials or can consist of one of the
following materials, for example: gold, nickel.
The first metallic layer is also referred to as a growth layer
("seed layer"). It does not necessarily have to consist of a single
layer. Rather, it is also possible that the first metallic layer is
a layer sequence made of multiple individual layers which are
different from one another. For example, the first metallic layer
can comprise a gold individual layer and a nickel individual layer
or can consist of a gold individual layer and a nickel individual
layer.
The second metallic layer is particularly preferably thicker than
the first metallic layer. The second metallic layer particularly
preferably has a thickness between 10 .mu.m inclusive and 100 .mu.m
inclusive. For example, the second metallic layer has a thickness
of approximately 60 .mu.m. The second metallic layer particularly
preferably has one of the following materials or is formed from one
of the following materials: silver, gold, nickel, copper.
The second metallic layer does not necessarily have to consist of a
single layer. Rather, it is also possible that the second metallic
layer is a layer sequence made of multiple individual layers which
are different from one another. For example, the second metallic
layer can comprise a silver individual layer and a nickel
individual layer or can consist of a silver individual layer and a
nickel individual layer.
It is also possible that the second metallic layer comprises a gold
individual layer and a nickel individual layer or consists of a
gold individual layer and a nickel individual layer.
Furthermore, the second metallic layer can comprise a nickel
individual layer, a copper individual layer, a further nickel
individual layer, and a silver individual layer or can consist of
these individual layers. The second metallic layer preferably has
these individual layers in the sequence as specified above in this
case, i.e., in the sequence nickel-copper-nickel-silver. The silver
individual layer can also be replaced by a gold individual layer in
this case.
The second metallic layer particularly preferably has lateral
flanks having an undercut. For example, the lateral flanks of the
second metallic layer are implemented as inclined in relation to a
normal of a main surface of the second metallic layer over a
partial region or over the entire length thereof, wherein the
cross-sectional area of the second metallic layer tapers from a
main surface facing toward the semiconductor body toward a main
surface facing away from the semiconductor body. The potting mass
particularly preferably encloses both the semiconductor bodies and
also the contact structures in a formfitting manner. The potting
mass particularly preferably forms a shared interface with the
semiconductor bodies and the contact structures. A second metallic
layer having lateral flanks having an undercut advantageously
contributes to better fixation of the potting mass within the later
component.
According to one embodiment of the method, in addition to the
radiation-emitting semiconductor bodies, further active elements,
for example, ESD diode chips (ESD stands for "electrostatic
discharge" in this case) are attached to the auxiliary carrier
wafer. For example, each later component can have an ESD diode
chip, which is provided to protect the component from excessive
electrical voltages.
According to one embodiment of the method, the potting mass is
implemented as reflective and/or wavelength-converting. The potting
mass particularly preferably has a matrix material, for example, an
epoxy, a silicone, a polyphthalanide (PPA), a polycyclohexylene
dimethylene terephthalate (PCT), or a mixture of at least two of
these materials. To implement the potting mass as reflective, for
example, reflective particles are embedded in the matrix material.
The reflective particles can contain one of the following materials
or consist of one of the following materials, for example: titanium
oxide, zinc white, for example, zinc oxide, lead white, for
example, lead carbonate.
Furthermore, the potting mass can also be implemented as
wavelength-converting, additionally or alternatively to the
reflective properties. The wavelength-converting potting mass is
preferably capable of converting electromagnetic radiation of the
first wavelength range into electromagnetic radiation of a second
wavelength range. For this purpose, for example, phosphor particles
are introduced into the matrix material of the potting mass, which
are capable of converting electromagnetic radiation of the first
wavelength range into electromagnetic radiation of the second
wavelength range. In other words, the phosphor particles preferably
provide the potting mass with the wavelength-converting
properties.
"Wavelength conversion" is understood in the present case in
particular as the conversion of incident electromagnetic radiation
of a specific wavelength range into electromagnetic radiation of
another, preferably longer-wave wavelength range. In particular,
during the wavelength conversion, electromagnetic radiation of an
incident wavelength range is absorbed by the wavelength-converting
element, converted by electronic processes at the atomic and/or
molecular level into electromagnetic radiation of another
wavelength range, and emitted again. In particular, the term
"wavelength conversion" does not mean solely scattering or solely
absorption of electromagnetic radiation in the present case.
The phosphor particles can have one of the following materials or
consist of one of the following materials, for example: garnets
doped with rare earth elements, alkaline earth sulfides doped with
rare earth elements, thiogallates doped with rare earth elements,
aluminates doped with rare earth elements, silicates doped with
rare earth elements, orthosilicates doped with rare earth elements,
chlorosilicates doped with rare earth elements, alkaline earth
silicon nitrides doped with rare earth elements, oxynitrides doped
with rare earth elements, aluminum oxynitrides doped with rare
earth elements, silicon nitrides doped with rare earth elements,
sialons doped with rare earth elements.
The potting mass can be processed, for example, using one of the
following methods: casting, dispensing, jetting, molding.
The auxiliary carrier wafer can be removed by one of the following
methods, for example: laser liftoff, etching, grinding. In general,
the auxiliary carrier wafer is removed in this case from an
interface, which is partially formed by a surface of the contact
structures and is partially formed by a surface of the potting
mass. In other words, the auxiliary carrier wafer generally forms a
shared interface, which is freely accessible after the removal of
the auxiliary carrier wafer, with the contact structures and with
the potting mass.
An auxiliary carrier wafer, which is transmissive to
electromagnetic radiation of a laser, is particularly preferably
removed by means of a laser liftoff process. The particular
advantage in this case is that the auxiliary carrier wafer is
essentially not destroyed during the laser liftoff process, so that
the auxiliary carrier wafer can optionally be reused after
corresponding conditioning.
A laser liftoff process is described, for example, in one of the
following documents, the content of the disclosure of which in this
regard is hereby incorporated by reference: WO 98/14986, WO
03/065420.
In particular, a carrier which has sapphire or glass or consists of
sapphire or glass is preferably removed using a laser liftoff
process.
An auxiliary carrier wafer which has a semiconductor material, for
example, silicon or consists of this material, is generally removed
by means of etching or grinding, in contrast. In this case, the
auxiliary carrier wafer is generally destroyed and cannot be
reused.
After the removal of the auxiliary carrier wafer, the resulting
composite made of optoelectronic components is generally isolated
and the colorimetric locus of the light emitted by the components
is measured.
According to a further embodiment of the method, a
wavelength-converting layer is arranged in a light path of the
semiconductor bodies. In this case, the wavelength-converting layer
can be provided in addition to a reflective potting mass. For
example, the wavelength-converting layer is applied to the entire
area on the reflective potting mass. The wavelength-converting
layer has wavelength-converting properties. For this purpose, the
wavelength-converting layer generally contains phosphor particles,
which are capable of converting radiation of the first wavelength
range into electromagnetic radiation of the second wavelength
range.
The wavelength-converting layer can be implemented, for example, as
a layered wavelength-converting potting mass. In other words, the
wavelength-converting layer can have, for example, a matrix
material, into which phosphor particles are introduced. The matrix
material having the phosphor particles can be implemented in the
form of a wavelength-converting layer by casting or printing, for
example. For example, the wavelength-converting layer can be
printed or cast on the potting mass.
Furthermore, it is also possible that the wavelength-converting
layer is created by a sedimentation method, in particular on the
potting mass.
In a sedimentation method, phosphor particles are introduced into a
matrix material. The surface to be coated is provided in a volume
which is filled with the matrix material having the phosphor
particles. Subsequently, the phosphor particles accumulate in the
form of a wavelength-converting layer on the surface to be coated
because of gravity. The settling of the phosphor particles can be
accelerated in this case by centrifuging. The use of a diluted
matrix material also generally accelerates the sedimentation
process. After the sinking of the phosphor particles, the matrix
material is cured.
A characteristic of a wavelength-converting layer which was applied
by means of a sedimentation method is that all surfaces on which
the particles can accumulate because of gravity are coated with the
wavelength-converting layer. Furthermore, the phosphor particles of
a sedimentary wavelength-converting layer are generally in direct
contact with one another.
The wavelength-converting layer can furthermore be created
separately, i.e., spatially remote, from the composite of later
optoelectronic components and can then be introduced into a light
path of the semiconductor bodies. For example, the matrix material
having the phosphor particles can be printed in the form of a layer
onto a film and then cured, so that a wavelength-converting layer
results. The wavelength-converting layer can then be introduced by
means of a pick-and-place method into the light path of the
semiconductor bodies. For example, the wavelength-converting layer
can be placed on the potting mass.
According to a further embodiment of the method, an optical element
is arranged in each case in the light path of each semiconductor
body. For example, a lens is positioned above each semiconductor
body downstream in the emission direction thereof. The optical
element can be molded above the semiconductor bodies, for example,
i.e., created with the aid of a cavity. The optical element can be
created, for example, using one of the following methods: injection
molding, casting, transfer molding, compression molding.
The semiconductor bodies can be implemented as flip-chips, for
example. A flip-chip has in particular two electrical contacts on a
mounting surface of the semiconductor body, while a
radiation-emitting front side of the flip-chip is free of
electrical contacts. In particular, flip-chips generally do not
require a bond wire for the electrical contacting. The electrical
contacts of the flip-chip are generally provided for mounting the
flip-chip on contact structures.
Furthermore, however, semiconductor bodies having one or two
electrical contacts on the front side, which is opposite to the
mounting surface thereof, can also be used. Such semiconductor
bodies can have a sapphire substrate, for example, on which a
radiation-emitting semiconductor layer sequence of the
semiconductor body is epitactically grown. Such semiconductor
bodies are also referred to as "sapphire chips". Sapphire is
generally an electrically insulating material. If the semiconductor
body therefore has a growth substrate, which has sapphire or
consists of sapphire, at least two electrical contacts are thus
generally arranged on the front side of the semiconductor body for
the electrical contacting. The mounting surface is generally formed
by an external surface of the growth substrate.
Furthermore, semiconductor bodies which only have a single
electrical contact on the front side thereof are also suitable. The
second electrical contact is arranged, for example, on the mounting
surface of the semiconductor body or formed by the mounting
surface. Such semiconductor bodies are also referred to as
"vertical" semiconductor bodies, since the current flow in
operation extends through the semiconductor body in the vertical
direction in parallel to a stack direction of the semiconductor
layer sequence.
A vertical semiconductor body can be, for example, a thin-film
semiconductor body. In a thin-film semiconductor body, a growth
substrate for the epitactic semiconductor layer sequence is
generally either completely removed or thinned such that it no
longer sufficiently mechanically stabilizes the epitactic
semiconductor layer sequence alone. Thin-film semiconductor bodies
generally comprise a carrier material, which is fastened on the
epitactic semiconductor layer sequence, for mechanical
stabilization. The carrier material is generally implemented as
electrically conductive, so that a vertical current flow is
possible from the front side to the mounting surface of the
semiconductor body. Thin-film semiconductor bodies are disclosed,
for example, in the document I. Schnitzer et al., Appl. Phys. Lett.
63 (16), 18 Oct. 1993, 2174-2176, the content of the disclosure of
which is hereby incorporated by reference.
Furthermore, semiconductor bodies which have a growth substrate,
which consists of silicon carbide or has silicon carbide, are
generally also implemented as vertical semiconductor bodies. A
vertical current flow is also possible in this case, since silicon
carbide is implemented as electrically conductive. Such
semiconductor bodies are described, for example, in document WO
01/61764, the content of the disclosure of which is hereby
incorporated by reference.
Later components, which only have a single vertical semiconductor
body, generally comprise contact structures having two structure
elements. The vertical semiconductor body is generally attached in
this case in an electrically conductive manner having its mounting
surface on a first contact structure element and is connected in an
electrically conductive manner via its front side to a second
contact structure element by means of a bond wire.
If the semiconductor body is a flip-chip, the rear electrical
contacts are generally each connected in an electrically conductive
manner to a contact structure element.
If the semiconductor body has at least two electrical contacts on
the front side, wherein the mounting surface of the semiconductor
body is free of electrical contacts, the semiconductor body can
thus be connected, for example, in an electrically conductive
manner to an electrical contact structure element on the front in
each case using a bond wire.
According to a further embodiment of the method, an upper edge of
the potting mass extends up to an upper edge of the second metallic
layer. In this case, the second metallic layer particularly
preferably forms an outer side of the contact structures. The
potting mass particularly preferably terminates flush with an upper
side of the second metallic layer in this case. The potting mass
particularly preferably covers the lateral surfaces of the second
metallic layer, while the lateral surfaces of the semiconductor
body are free of the potting mass. In this embodiment of the
method, the application of the potting mass can be performed before
or after the application of the semiconductor bodies to the
auxiliary carrier wafer.
According to a further embodiment of the method, the upper edge of
the potting mass extends up to an upper edge of the semiconductor
bodies. In this case, the potting mass particularly preferably
terminates flush with the front side of the semiconductor bodies.
The potting mass particularly preferably completely covers each of
the lateral surfaces of the semiconductor bodies in this case, but
does not protrude beyond the front side of the semiconductor
bodies. This embodiment is advantageous if a reflective potting
mass is used in particular in the case of a semiconductor body
which is not provided for emitting electromagnetic radiation via
its lateral surfaces, for example a thin-film semiconductor body
having a silicon or germanium carrier. In this embodiment of the
method, the potting mass is applied after the application of the
semiconductor bodies to the auxiliary carrier wafer.
Furthermore, it is also possible that the upper edge of the potting
mass extends beyond the second metallic layer, but does not extend
up to the upper edge of the semiconductor body. In this case, it is
also possible that the potting mass does completely encapsulate the
lateral flanks of the contact structures, but the lateral surfaces
of the semiconductor body are arranged spaced apart from the
potting mass. In this embodiment of the method, the application of
the potting mass can also be performed before or after the
application of the semiconductor bodies to the auxiliary carrier
wafer.
If a reflective potting mass is used, the lateral surfaces of the
semiconductor body are particularly preferably arranged spaced
apart from the potting mass or are free of the potting mass, if
radiation of the semiconductor body can also be emitted via the
lateral surfaces of the semiconductor body, as is the case in
particular with a semiconductor body having a
radiation-transmissive growth substrate, such as sapphire or
silicon carbide.
According to a further embodiment of the method, a mechanically
stabilizing material is molded around the contact structures. The
mechanically stabilizing material is particularly preferably used
for stabilizing the finished optoelectronic component and fulfills
the function of a housing, for example. In contrast to a
conventional housing, however, the mechanically stabilizing
material is not implemented as a separate element, onto or into
which the semiconductor body is mounted.
The mechanically stabilizing material is particularly preferably
molded around the contact structures before the plurality of
semiconductor bodies are encapsulated using the potting mass. The
mechanically stabilizing material is, for example, a high-stability
housing material, such as high-stability polyphthalamide (PPA) or
high-stability epoxy.
The mechanically stabilizing material particularly preferably forms
a shared interface with the contact structures. An upper edge of
the mechanically stabilizing material particularly preferably
terminates flush laterally with an upper edge of the contact
structures.
The potting mass material, which is molded around the semiconductor
bodies, is particularly preferably applied subsequently to the
mechanically stabilizing material.
The mechanically stabilizing material can particularly preferably
be implemented as molded around the contact structures, for
example, by means of molding, i.e., with the aid of a casting tool,
which is particularly preferably implemented as flat.
According to a further embodiment of the method, each later
component has a plurality of semiconductor bodies. For example, the
semiconductor bodies can be provided for emitting light of
different wavelengths.
The later optoelectronic components can be, for example,
light-emitting diodes.
According to one embodiment, the finished components are provided
to emit white light. For this purpose, each component generally
comprises a wavelength-converting element, for example, a
wavelength-converting layer or a wavelength-converting potting
mass. The wavelength-converting element preferably converts a part
of the electromagnetic radiation of the first wavelength range
emitted by the semiconductor body into electromagnetic radiation of
the second wavelength range. The first wavelength range preferably
comprises blue light and the second wavelength range preferably
comprises yellow light. In this case, the component preferably
emits mixed-color white light, which is formed from unconverted
blue light and converted yellow light.
Further advantageous embodiments and refinements of the invention
result from the exemplary embodiments described hereafter in
conjunction with the figures.
A first exemplary embodiment of the method is described on the
basis of the schematic sectional illustrations of FIGS. 1 to 5.
A further exemplary embodiment of the method is described on the
basis of the schematic sectional illustrations of FIGS. 6 to
10.
A further exemplary embodiment of the method is described in each
case on the basis of the schematic sectional illustrations of FIGS.
11 and 13 to 19.
FIG. 12 shows an example of an electron microscope picture of an
undercut of a second metallic layer.
Identical, similar, or identically acting elements are provided
with the same reference signs in the figures. The figures and the
size relationships of the elements illustrated in the figures among
one another are not to scale. Rather, individual elements, in
particular layer thicknesses, can be shown exaggeratedly large for
better illustration ability and/or for better comprehension.
In the method according to the exemplary embodiment of FIGS. 1 to
5, an auxiliary carrier wafer 1 is provided in a first step (FIG.
1). The auxiliary carrier wafer 1 has in particular glass,
sapphire, or a semiconductor material, for example, silicon. A
first metallic layer 2 is applied to the auxiliary carrier wafer 1.
The first metallic layer 2 is implemented as structured. In other
words, the first metallic layer 2 has various structural
elements.
In a further step, a second metallic layer 3 is galvanically
deposited on the first metallic layer 2 (FIG. 2). The second
metallic layer 3 is also implemented as structured. The structuring
of the second metallic layer 3 follows the structuring of the first
metallic layer 2 in this case. The first metallic layer 2 and the
second metallic layer 3 together form contact structures 4 having
individual contact structure elements 41.
In a further step, a plurality of semiconductor bodies 5, which are
capable of emitting electromagnetic radiation from the radiation
exit surface 6 thereof, are now applied to the contact structures 4
(FIG. 3). Each semiconductor body 5 is applied in this case with a
mounting surface 7 on a contact structure 41 in an electrically
conductive manner, for example, by gluing, soldering, or die
bonding.
In a next step, each semiconductor body 5 is now connected with its
front side 9 by means of a bond wire 8 in an electrically
conductive manner to a further contact structure element 41 (FIG.
4).
In a next step, a potting mass 10 is applied to the auxiliary
carrier wafer 1, so that the contact structures 4 and the
semiconductor bodies 5 are encapsulated using the potting mass 10
(FIG. 5). The potting mass 10 completely encloses in this case both
the contact structure elements 41 of the contact structures 4 and
also the semiconductor bodies applied thereon. The bond wires 9 are
also completely enclosed by the potting mass 10. The potting mass
10 protrudes beyond the radiation exit surface 6 of the
semiconductor bodies 5 and is located in a light path 12 of the
semiconductor bodies 5.
In the present exemplary embodiment, the potting mass 10 is
implemented as layered. The layer of the potting mass has an
essentially constant thickness in this case. Furthermore, the
potting mass 10 is implemented as wavelength-converting in the
present exemplary embodiment. For this purpose, the potting mass 10
comprises a matrix material having phosphor particles 11, which are
capable of converting radiation of a first wavelength range, which
is emitted from the semiconductor bodies 5, into electromagnetic
radiation of a second wavelength range. Since the potting mass 10
is located in the light path 12 of the semiconductor bodies 5, the
electromagnetic radiation of the first wavelength range, which is
emitted from the semiconductor bodies 5, is partially converted
into electromagnetic radiation of a second wavelength range. In the
present case, the semiconductor bodies 5 particularly preferably
emit blue light, which is partially converted by the phosphor
particles in the potting mass 10 into yellow light. The finished
components emit mixed-color white light in the present exemplary
embodiment.
In a next step, the auxiliary carrier wafer 1 is detached from the
composite of the later components, the contact structures 4,
semiconductor bodies 5, and wavelength-converting potting mass 10
(not shown). Subsequently, the later components, which each
comprise a single semiconductor body 5, are isolated (not
shown).
In the method according to the exemplary embodiment of FIGS. 6 to
10, firstly the method steps which were already described on the
basis of FIGS. 1 to 4 are carried out. A potting mass 10 is then
applied to the auxiliary carrier wafer 1, which completely
encapsulates the contact structures 4 and partially encapsulates
the semiconductor bodies 5 (FIG. 6). A partial region of the
lateral flanks of the semiconductor bodies 5 and the radiation exit
surface 6 of the semiconductor bodies 5 remain free of the potting
mass 10. The potting mass 10 is implemented as reflective in the
present exemplary embodiment. For this purpose, the potting mass 10
comprises a matrix material, into which reflective particles 13,
for example, titanium oxide particles, are introduced.
In a next step, a wavelength-converting layer 14 is applied to the
reflective potting mass 10 (FIG. 7). The wavelength-converting
layer 14 encloses in this case the regions of the lateral surfaces
of the semiconductor body 5 which are not enclosed by the
reflective potting mass 10. Furthermore, the wavelength-converting
layer 14 protrudes beyond the semiconductor bodies 5, so that it is
located at least partially in the light path 12 of the
semiconductor bodies 5.
The wavelength-converting layer 14 comprises a matrix material,
into which phosphor particles 11 are introduced. The phosphor
particles 11 provide the wavelength-converting layer 14 with its
wavelength-converting properties.
In a next step, a plurality of optical elements 15 is applied to
the wavelength-converting layer 14 (FIG. 8). The optical elements
15 are each implemented as a lens. Each optical element 15 is
positioned over one semiconductor body 5 in each case and is
located in the light path 12 thereof. The optical element 15 can,
for example, be molded onto the wavelength-converting layer 14,
i.e., implemented by means of a cavity.
In a next step, the auxiliary carrier wafer 1 is completely removed
from the composite of the later semiconductor components (FIG. 9).
If the auxiliary carrier wafer 1 is a sapphire substrate or a glass
carrier, it can thus be removed by means of a laser liftoff
process. If a silicon carrier is used as the auxiliary carrier
wafer 1, it is thus generally removed destructively, i.e., by means
of grinding or etching, for example, from the composite of the
later components. In a further step, the components are isolated
(FIG. 10).
In the method according to the exemplary embodiment of FIG. 11, as
in the preceding exemplary embodiments, an auxiliary carrier wafer
1 is provided, onto which contact structures 4 are applied. FIG. 11
shows in this case a portion of the auxiliary carrier wafer 1,
which contains a semiconductor body 5 and corresponds to a finished
component. The contact structures 4 comprise multiple contact
structure elements 41, wherein a radiation-emitting semiconductor
body is applied to a contact structure element 41. The
semiconductor body 5 is connected in an electrically conductive
manner on the front to a further contact structure element 41 using
a bond wire 8.
The contact structures 4 have a first metallic layer 2 and a second
metallic layer 3. In contrast to the above-described exemplary
embodiments, the second metallic layer 2 has lateral flanks having
an undercut. Each contact structure element 41 has lateral flanks
in this case, which extend inclined in relation to a normal of the
auxiliary carrier wafer 1 over a partial region. Because of the
inclined lateral flanks of the second metallic layer 3, the contact
structure element 41 tapers from an outer surface of the contact
structure element 41 toward the auxiliary carrier wafer 1. The
undercut of the second metallic layer 3 is provided to anchor the
potting mass 10 better. The reflective potting mass 10 is applied
in the present case up to an upper edge of the second metallic
layer 2. A surface of the reflective potting mass 10 terminates
flush with a surface of the contact structures 4.
FIG. 12 shows an example of an electron microscope picture of an
undercut of a lateral flank of a second metallic layer 2.
In the method according to the exemplary embodiment of FIG. 13, in
contrast to the exemplary embodiment according to FIG. 11, the
reflective potting mass 10 is applied up to the radiation exit
surface 6 of the semiconductor body 5. The surface of the potting
mass 10 terminates flush with the radiation exit surface 6 of the
semiconductor body 5.
In the method according to the exemplary embodiment of FIG. 14, the
reflective potting mass 10 is applied, in contrast to the method of
the exemplary embodiments of FIGS. 11 and 13, such that the surface
of the potting mass is located below the radiation exit surface 6
of the semiconductor body 5. The potting mass 10 does encapsulate
the metallic contact structures 4 over their entire height in this
case, so that the lateral flanks of the contact structures 4 are
completely enclosed by the potting mass 10, however, an air gap is
implemented between the lateral surfaces of the semiconductor body
5 and the potting mass 10.
In the above-described exemplary embodiments, vertical
semiconductor bodies 5 are used in each case, which are connected
in an electrically conductive manner on the rear via a mounting
surface 7 to a first contact structure element 41 and on the front
to a second contact structure element 41. The electrically
conductive connection from the front side 9, which is opposite to
the mounting surface 7, of the semiconductor body 5 to the contact
structure element 41 is performed in this case via a bond wire
8.
In contrast to the exemplary embodiment of FIG. 11, a semiconductor
body 5 is used in the exemplary embodiment according to FIG. 15, in
which two electrical contacts are arranged on its front side 9. The
semiconductor body 5 is, for example, a sapphire chip. The
semiconductor body 5 is connected in a conductive manner on the
front using two bond wires 8 to a contact structure element 41 in
each case.
In contrast to the exemplary embodiments of FIGS. 11 and 15, in the
exemplary embodiment according to FIG. 16, a flip-chip is used as
the semiconductor body 5. The flip-chip has two electrical contacts
on its mounting surface 7, which are each connected in an
electrically conductive manner to a contact structure element 41,
for example, by means of soldering.
In the exemplary embodiment according to FIG. 17, in contrast to
the above-described exemplary embodiments, a mechanically
stabilizing material 16, for example, a housing material, is molded
around the contact structure elements 41. The mechanically
stabilizing material 16 terminates flush with a surface of the
contact structure elements 41 in this case. Furthermore, a potting
mass 10, which is implemented as reflective in the present case, is
applied to the surface which is formed by the contact structure
elements 41 and the surface of the mechanically stabilizing
material 16. The reflective potting mass 10 is applied in this case
in the form of a layer to the contact structure elements 41 or the
housing material 16 and terminates flush with a front side 9 of the
semiconductor body 5.
In the exemplary embodiment according to FIG. 18, a later component
is created, which comprises multiple semiconductor bodies 5. The
semiconductor bodies 5 are particularly preferably provided to emit
electromagnetic radiation of different wavelength ranges. The
wavelength ranges are particularly preferably selected such that
the finished component emits white light in operation. The
semiconductor bodies 5 are each applied on the rear in an
electrically conductive manner with their mounting surface 7 to a
shared contact structure element 41. On the front, the
semiconductor bodies 5 are contacted with one another in an
electrically conductive manner in each case using a bond wire 8.
The two semiconductor bodies 5 which are arranged at the edge are
each additionally connected in an electrically conductive manner on
the front via a bond wire 8 to a further contact structure element
41. The semiconductor bodies 5 are serially powered in operation of
the later component.
A component which has a plurality of semiconductor bodies 5 is also
produced in the method according to the exemplary embodiment of
FIG. 19. In contrast to the preceding exemplary embodiment,
however, the semiconductor bodies 5 are electrically contacted in
parallel. For this purpose, the semiconductor bodies 5 are each
connected in an electrically conductive manner on the front via a
bond wire 8 to a shared further contact structure element 41.
The present application claims the priority of German application
DE 10 2013 100 711.2, the content of the disclosure of which is
hereby incorporated by reference.
The invention is not restricted thereto by the description on the
basis of the exemplary embodiments. Rather, the invention comprises
every novel feature and every combination of features, which
includes in particular every combination of features in the patent
claims, even if this feature or this combination is not explicitly
specified itself in the patent claims or exemplary embodiments.
* * * * *